Method of isolating caramel color values



United States Patent METHOD OF ISOLATIN G CARAMEL COLOR VALUES Granite'City, to Union Starch & Refining Company, Ind., a corporation ofIndiana No Drawing. Application February 6, H56 Serial No. 563,407

4 Claims. (Cl. 99-148) This invention relates to a process of isolatinghigh color polymers from burnt or caramelized sugar compositions.

This application is a continuation-in-part of U. S. appli cation SerialNo. 268,142, filed January 24, 1952.

Burnt sugar coloring or caramel color contains a substantial quantity ofunchanged sugar. The polymers contributing coloring power constituteonly a minor part of the total weight, ordinarily not over 25-30%. Itwould be very advantageous to be able to convert a large quantity of thesugar to color polymers in burning processes but this is exceedinglydifiicult to do or perhaps impossible by means of practical, large scaleprocedures. A certain limit is reached in direct burning whereinstability results if the burning process is continued. Apparentlypolymerization proceeds too far as manifested by a very sharply risingviscosity and diminished solubility. The reaction can be continued untilan insoluble gel is obtained and this develops long before all the sugaris consumed in the burning process. This result must be avoided incommercial burning processes and they are stopped after relatively lowyields of color are produced. Much effort has been expended in anattempt to increase the yield of color from a given quantity of sugar bymodifications of burning procedures, catalyst systems, etc., but withoutmuch success. The practical limit has remained fixed within fairlynarrow confines for many years.

There is another approach to this problem that has been more rewardingin increasing the yield of color from sugar. This method involvesburning to the practical limit of stability and then separating thecolor imparting polymers, which are in colloidal form, by any means thatcan be used to remove the colloidal phase from the crystalloids. Thelatter (sugars) are then burned to yield another crop of colloidalcoloring polymers and the operation is repeated until all the sugars areconverted to color. This is a practical method but a complicated processinvolving very large capital investment in equipment, reagents, etc.Such a method is disclosed and claimed in our U. S. Patent No.2,533,221.

Among the objects of this invention is to provide a simplified method ofutilizing the unburned or residual sugarsto make useful products andthereby making a caramel color of greater coloring ability or aconcentrated color.

Among other objects of this invention is to provide a method forisolating the coloring compounds from caramel color and for utilizingthe unconverted sugar to make useful products in the course of theprocessing operation.

It may contribute to the ready comprehension of this invention to pointout here that all of the caramelcolors of commerce unless processedafter burning are very resistant to attack by microorganisms. This iscaused by the fact thata number of very eflicient inhibitors to theirgrowth are formed in the burning operation and as by-products of thepyrolysis of sugars. Hence it is possible to dilute an ordinary caramelcolor with several parts 2,873,193 Patented Feb. 10, T959 of water,inoculate with large quantities of very potent yeast, mold spores, etc.,and still find it impossible to induce any appreciable fermentationunder the most favorable temperature conditions possible for incubationor proliferation of the organisms. This property of ordinary commercialcaramel colors is widely recognized and relied upon by some users whodepend on the caramel color to provide protection against spoilage oftheir more susceptible mixtures. A well known fermentation test iswidely used to evaluate this bacteriostatic property of caramel color.

This invention is based on the discovery that contrary to generalbelief, the bacterial inhibitors are removable from caramel color byseveral relatively simple methods. The unexpected result is that theunpolymerized sugars in caramel color then become very readilyfermentable and/or subject to attack by microorganisms or enzymes andcapable of producing relatively high yields of fermentation or similarproducts. The color bodies are on the other hand very resistant toattack by any of the common organisms. It is upon this unexpectedcombination of circumstances that this invention depends. By subjectingthe unburned sugars in the caramel color to fermentation processes theyare converted into useful substances that are readily separable from thecolor producing compounds which are thereby isolated and can beconcentrated.

The above cited objects and others ancillary thereto are obtained by (1)providing a caramelized sugar solution, (2) removing bacterialinhibitors from the solution, (3) fermenting or otherwise treating theresultant composition to change the non color sugar bodies remaining inthe product to useful commercial products and (4) separating the colorbodies from the thus produced commercial products.

The caramelized sugar solution may be made in any known way from any ofthe commercially available sugar solutions.

The bacterial inhibitors may be removed or deactivated in any way whichdoes not affect quality of the color bodies. These inhibitors appear tobe by-products of the pyrolysis of sugars and to have greater volatilityand greater solubility than the sugars of the said] color bodies. At anyrate the inhibitors can be removed by distillation of the dilutedsolution, by preferential solvent extraction or by ion exchangers.

The fermentation may be carried out with yeasts, en-

zyme s, moulds, bacteria or other microorganisms capable of changingsugars to useful commercial products. Many such processes are known andutilized to produce various organic acids, alcohols, organic solvents,etc.

Yeasts which are suitable strains of Saccharomyces cerevisiae may beemployed for the production of ethyl alcohol from the sugars in thesyrup. With such yeasts, temperatures of around 2833 C. may be employedafter the pH of the mix is adjusted to about 4.0 to 5.0. S. anamensis orS. pombe may also be employed. Saccharomyces ellipsoideus (varSteinberg) and S. ellipsoideus (var. California) yeasts may be employedfor the production of glycerol from the glucose and similar componentsof the caramel syrup.

Molds such as Aspergillus niger, A. aureus, A. clavatus, P. luleum, P.citrz'num, Ustulina vulgaris etc. may be employed for the production ofcitric acid from the glucose and similar components of the caramelsyrup. Aspergillus niger (Strain 67) or the presence of calciumcarbonate may be employed for the production of gluconic acid from thesaid glucose and similar components. P. chrysogenum (Culture 5,034,11)may also be employed for the production of gluconic acid in the presenceof sodi um nitrate, potassium dihydrogen phosphate and magnesiumsulfate.

Bacteria such as Bact. putidum may be employed for the production ofgluconic acid or calcium gluconate. Various acetobacter speciesofbacteria Acetobacter aceti may be employed for the production of aceticacid from the glucose,

Instead of the microorganisms themselves, as mentioned above, specificenzymes derived from the microorganisms may be employed to convert theglucose of the caramel liquor to a non sugar product which may beseparated and recovered from the liquor.

It will be realized that the process of separating the color bodies fromthe organic reagent produced by the fermentation or other treatment willvary depending on the type of organic reagent produced. Decantation,solvent extraction, crystallizatio-n, reaction of organic acids withalkaline precipitants and various other known chemical and physicalmethods ofseparation may be employed. The following description oftypical applications of the invention are given by way of illustrationbut are not to be construed in a limiting sense.

Example 1 One thousand gallons of caramel color produced by aconventional burnirn process and having a tinctorial power of 25 to 30units (A solution of 1.0 gram in 1000 ml. of water is matched in a /2cell against Lovibond Series No. 52 caramel color slides.) is dilutedwith water to about 36. The excess water is evaporated in a vacuum pan,at not less than 26 of vacuum, until the Baum is increased to about 38".In this manneressentially all of the effective bacterial inhibitors passoif with the vapor and are removed from the caramel color. It will befound that the sugars in the solution are now readily fermentable byyeast and other organisms when adjusted to a favorable concentration.

After the inhibitors have been removed by the above describeddistillation step the caramel color is again diluted to about 20 Be.with water and is inoculated with a culture of Aspergillus niger. Thisorganism requires a considerable quantity of oxygen to thrive and thefermentation is accordingly conducted in shallow pans or caused tocirculate in a cascade system over a series of trays. Citric acid can beproduced by this method in satisfactory yields and when the fermentationhas proceeded to completion the acid produced is neutralized with limeto make calcium citrate. This compound is relatively insoluble in theaqueous solution and may be separated by decantation and filtration.

The mother liquor from which the sugars have been removed by the aboveprocess is heated to about 180 F. and is again filtered through a heavyprecoating of diatoinaceous filter aid in order to remove theinactivated spores, coagulated proteins and residual calcium salts, etc.Following this step the pH of the mother liquor is adjusted to 2.5-3.0and concentrated to about 50% solids in a vacuum evaporator. The resultis a solution of relatively pure color bodies or color impartingpolymers and a very desirable form of caramel color for beverages, etc.It has a tinctorial power several times that of the caramel color fromwhich it was made on an equal solids basis. It may be dried to a powderand is relatively non-hygroscopic in comparison with the ordinary drycaramel colors.

it is obvious that once the bacterial inhibitors are removed from thecaramel color in accordance with the methods of our invention the sugarsare fermentable and may be subjected to any useful type of fermentationto make alcohols, other organic acids or any other of the productsnormally made by the action of microorganisms on's i'gars.

The type of vacuum distillation described is not the only niearis ofremoval of the volatile inhibitors. These may be simply boiled 03 fromdilute solutions by evaporating at atmospheric pressure but this methodis of much lower e'flici'eiicyb'oth in respect to steam consumption-"andconfb '4 plete removal of the inhibiting constituents. More elaborateequipment than a simple vacuum pan may be used to advantage also. Wehave had good results with a vegetable oil deodorizer that works on theprinciple of subjecting the liquid to a steam scrubbing operation undervacuum in a countercurrent system in which the caramel color flows overa series of plates equipped with bubble caps.

Example 2 The caramel color is diluted and the bacterial inhibitors,etc., are removed as set forth in Example 1. After the inhibitors havebeen removed, the caramel color liquor is again diluted to about 20 B.with water and is inoculated with Saccharomyces cerevisiae (yeast). Thisorganism will react with the sugar in caramel color in tanks producingethyl alcohol and carbon dioxide. The ethyl alcohol is removed by vaccumdistillation during the final concentration period of the pure caramelbodies.

The fermentation reaction is maintained at temperatures of 28-33 C. andat a pH range of 4050 for the best results.

The mother liquor from which the sugars have been removed by the aboveprocess is heated to F. and is filtered through a heavy precoating ofdiatomaceous filter aid in order to remove the inactivated yeast spores,coagulated protein, etc. Following this step the pH of the mother liquoris adjusted to 2.5-3.0 and concentrated to about 50% solids in a vacuumevaporator. As mentioned above the vapors can be passed through a rectifying column in order to separate the ethyl alcohol from the watervapors. The resulting color bodies will have the same properties andtinctorial power as set forth in Example 1. 7

Example 3 t The caramel color is diluted and the bacterial inhibitors,etc., are removed as set forth in Example 1.

After the inhibitors have been removed the carame color liquor is againdiluted to about 20 B. with water and is inoculated with a culture ofbacterium putidum. This organism requires a considerable quantity ofoxygen to thrive and the fermentation is accordingly conducted inshallow pans or caused to circulate in a cascade system over a series oftrays or bottles. Gluconic acid is produced by this method insatisfactory yields and when the fermentation has proceeded tocompletion the acid produced is neutralized with lime to make calciumgluconate. This compound is relatively insoluble in the aqueous solutionand is separated by decantation and filtration.

The mother liquor from which the sugars have been removed can beprocessed in the same manner as out lined in Example 1.

We claim:

1. A process for separating the color bodies from caramelizedcarbohydrate solutions comprising the steps of providing a caramelizedsugar solution containing caramel color bodies, residual uncaramelizedsugar and fermentation inhibiting constituents formed insitu when thesugar is caramelized, removing the fermentation inhibiting constituents,thereafter inoculating the solution with an organism adapted to changethe residual uncaramelized sugar to a different material of lower mo?lecular weight, and separating the said different material of lowmolecular weight from the caramel color bodies.

2. A process for separating the color bodies from caramelizedcarbohydrate solutions comprising the steps of providing a caramelizedsugar solution containing caramel color bodies, residual uncaramelizedsugar and fermentation inhibiting constituents formed in situ when thesugar is caramelized, diluting the solution with an aqueous liquidremoving the fermentation inhibiting constituents by distilling waterfrom the solution, thereafter inoculating the solution with an organismadapted to change the residualuncaramelized sugar to an alcohol;

and separating said alcohol from the caramel color bodies.

3. A process for separating the color bodies from caramelizedcarbohydrate solutions comprising the steps of caramelizing a sugarsolution by heat treating it under caramelizing conditions to providethereby a solution containing caramel color bodies, residualuncaramelized sugar and fermentation inhibiting constituents formed insitu when the sugar is caramelized, diluting the solution with anaqueous liquid, removing the fermentation 1 inhibiting constituents,thereafter inoculating the solution with an organism adapted to changethe residual uncaramelized sugar to a different material of lowermolecular Weight, and separating the said different material of lowmolecular Weight from the caramel color bodies. 15

4. A process for separating the color bodies from caramelizedcarbohydrate solutions comprising the steps of providing a caramelizedsugar solution containing caramel color bodies, residual uncaramelizedsugar and fermentation inhibiting constituents formed in situ when thesugar is caramelized, diluting the solution with aaqueous liquid,removing the fermentation inhibiting constituents by distilling waterfrom the solution, thereafter inoculating the solution with an organismadapted to change the residual uncaramelized sugar to a differentmaterial of lower molecular Weight, and separating the said differentmaterial of low molecular Weight from the caramel color bodies.

References Cited in the file of this patent UNITED STATES PATENTS2,142,739 Wallace Jan. 3, 1939

1. A PROCESS FOR SEPARTING THE COLOR BODIES FROM CARAMELIZEDCARBOHYDRATE SOLUTIONS COMPRISING THE STEPS OF PROVIDING A CARAMELIZEDSUGAR SOLUTION CONTAINING CARAMEL COLOR BODIES, RESIDUAL UNCARAMELIZEDSUGAR AND FERMENTATION INHIBITING CONSTITUENTS FORMED IN SITU WHEN THESUGAR IS CARAMELIZED, REMOVING THE FERMENTATION INHIBITING CONSTITUENTS,THEREAFTER INOCULATING THE SOLUTION WITH AN ORGANISM ADAPTED TO CHANGETHE RESIDUAL UNCARAMELIZED SUGAR TO A DIFFERENT MATERIAL OF LOWERMOLECULAR WEIGHT, AND SEPARATING THE SAID DIFFERENT MATERIAL OF LOWMOLECULAR WEIGHT FROM THE CARAMEL COLOR BODIES.